Earthquakes primarily affect the Earth’s solid crust, and their direct impact on airborne aircraft is generally minimal. While planes are designed to withstand various forces encountered during flight, the main concerns related to seismic activity involve ground-based operations and airport infrastructure. The potential for disruption arises not from the direct interaction of seismic waves with an aircraft in the sky, but from the effects these events have on the facilities and systems that support air travel.
Direct Atmospheric Effects on Aircraft
Seismic waves travel predominantly through the Earth’s interior and along its surface. There are two main types: P-waves (primary waves) and S-waves (secondary waves). P-waves are compressional waves that can travel through solids, liquids, and gases, similar to sound waves. S-waves, however, can only travel through solids.
While P-waves can transfer into the atmosphere as infrasound waves, these atmospheric disturbances are too weak and dissipate rapidly with distance and altitude to affect a plane at cruising height. The energy from an earthquake attenuates significantly as it moves through the air, making any vibrations or pressure changes at an aircraft’s altitude imperceptible against the plane’s own motion and engine noise. Therefore, an airplane in flight would not experience direct physical effects from an earthquake below.
Impacts on Airport Operations and Infrastructure
Earthquakes primarily affect aviation through damage to ground infrastructure. Airport facilities, including runways, taxiways, and buildings like terminals and control towers, can sustain considerable damage. For instance, a 7.8 magnitude earthquake in Turkey caused a runway at Hatay Airport to split, rendering it unusable. The 1989 Loma Prieta earthquake also damaged the runway at Metropolitan Oakland International Airport due to liquefaction. Critical utilities such as power and communication lines are also vulnerable, potentially leading to widespread disruptions.
Soil liquefaction, a phenomenon where saturated granular material loses strength and behaves like a liquid during seismic shaking, can cause runways to crack and settle, making them unsafe for aircraft operations. Airports located in seismically active regions undertake seismic vulnerability assessments of their infrastructure to identify and mitigate these risks. These assessments help in planning for potential damage to structural and non-structural systems, aiming for operational continuity even after a significant seismic event.
After an earthquake, airports initiate immediate assessment procedures to ensure structural integrity and operational safety. Airfield operations teams inspect runways and taxiways for cracks, debris, or imperfections that could endanger aircraft. These checks are paramount before resuming flights to confirm that the airport can safely handle aircraft movements.
Air Traffic Management and Safety Protocols
When an earthquake occurs near an airport, Air Traffic Control (ATC) plays a central role in managing the airspace and ensuring safety. As a precautionary measure, the Federal Aviation Administration (FAA) may issue ground stops, temporarily preventing aircraft from taking off from affected airports while facilities are assessed for damage. This allows ground crews to inspect runways, taxiways, and buildings for structural compromise or debris.
Pilots approaching an affected airport are instructed by ATC to hold or divert to alternative airports if the runway is deemed unsafe or if communication systems are compromised. Airports and air traffic management facilities have emergency response plans that include coordination with various agencies, such as fire and rescue services, to ensure a rapid response. These plans outline roles, responsibilities, communication protocols, and resource allocation for post-earthquake scenarios.
Safety is paramount in aviation, leading to a cautious approach to resuming operations even after minor tremors. Aircraft that were on the ground during an earthquake may undergo specific inspections to check for potential damage, especially if they were connected to ground support equipment or jet bridges. Coordinated efforts between ATC, airport authorities, and emergency services aim to restore operations quickly while prioritizing passenger and personnel safety.